The test classloader is created here, but never closed. As a result, the underlying JARs in that classloader remain open and cannot be deleted. Also, their content can be stale when opened using java.util.ZipFile.
This is a problem when running Maven integration tests using the Embedded3xLauncher. We are developing a Maven extension and want to make sure it works well with surefire/failsafe. This classloader leak means we have to use a forking launcher instead, which slows down our tests considerably.